1. Field of the Invention
This invention relates generally to a method and apparatus for self-testing a transducer system. The sensitivity of the system is determined by measuring the average value of the product of a test signal and the system output with the test signal applied. Any constant component of the test signal is removed before the product taken. Optimum performance is obtained by utilizing a random or pseudo-random test signal. The method and apparatus may utilize either analog or digital techniques.
2. Description of the Prior Art
The prior art includes self-testing systems for use with transducers and their associated circuitry. However, most prior art systems run the self-test while the transducer system itself is not operational for its intended purpose or not receiving environmental signals.
Those prior art systems that do run a self-test while the transducer system is operational, usually produce a highly inaccurate or ambiguous test result output which has a relatively low reliability due to the presence of very significant noise and/or error terms.
The present invention provides an improved method and apparatus for self-testing transducer systems while they are operational, while simultaneously providing for a high degree of accuracy in the test result output signal. This method and apparatus uses a uniquely-tailored self-testing signal selected to have specific properties which guarantee the minimization of the magnitude of the error terms produced.
In fact, the method and apparatus of the present invention provide a highly accurate and unambiguous test result along with one or more error or noise terms whose values tend to zero over the test time period and whose magnitudes decrease as the test time increases.
Therefore, the present invention solves substantially all of the problems of the prior art, while simultaneously avoiding any of its shortcomings and new problems, by utilizing an improved method and apparatus of self-testing with a self-test signal having unique properties, as described herein.